Lightweight solar concentrator cell array

Abstract

A self supporting solar concentrator cell array adapted for use in space applications that includes a plurality of cylindric parabolic reflective mirror surfaces, each of which focus recipient sunlight forwardly onto a focal line which is positioned approximately on the backside of an adjacent mirror surface on which is secured a solar element for converting the focussed sunlight into electricity. A front element extending upwardly from the leading edge of each mirror surface cooperates in providing an aperture through which the focussed sunlight passes and side elements close each cell element. The backside of each mirror is provided with a thermally emissive surface to provide mirror thermal control and allows the mirror to act as a thermal radiator fin for the solar cell elements. The mirror surface is provided with a highly reflective coating such as aluminum or silver to optimize reflectivity. The solar cell concentrator cell array is made by forming an uncured advanced organic composite part blank over a highly polished tool surface to impart the desired mirror surfaces. The solar concentrator cell array is cured, for example, by heated press means to form a unitary integral cell array that is entirely self supporting and provides structural stability while providing optimum electrical power output for minimum weight.

What is claimed is: 
     
       1. A solar concentrator cell element usable in outer space, which comprises: a longitudinally extending mirror element which is provided with an off-axis cylindric parabolic reflective surface that has a predetermined focal line and which is adapted to receive sunlight and to concentrate such light at the focal line;   a front element which extends upwardly from the lower leading edge of the mirror element, said front element being provided with a longitudinally extending aperture which is sufficiently large to permit light reflected from the mirror to pass through; and   solar cell means adapted to convert sunlight into electricity which is positioned on the backside of the mirror for receiving concentrated light passing through an aperture of the front apertured element of an adjacent solar concentrator cell.   
     
     
       2. The solar concentrator cell element of claim 1 which further includes spaced end elements that are secured to each end of the mirror element, with the mirror element and the end element being integrally formed from an organic composite material. 
     
     
       3. The solar concentrator cell element of claim 1 wherein said end elements are formed from a different composite material than said mirrors. 
     
     
       4. The solar concentrator cell element of claim 2 wherein the reflective surface of the mirror includes a coating of a highly reflective metal and a thin transparent protective film deposited over the metal coating. 
     
     
       5. The solar concentrator cell element of claim of claim 4 wherein the reflective metal is chosen from a group consisting of aluminum and silver. 
     
     
       6. The solar concentrator cell element of claim 2 wherein the reflective surface of the mirror comprises a metallized film bonded to the organic composite material of the mirror. 
     
     
       7. The solar concentrator cell element of claim 6 wherein the metallized film is chosen from a group consisting of aluminized Mylar, silvered Mylar, Aluminized Teflon, aluminized Kapton, silvered Kapton and silvered Teflon. 
     
     
       8. The solar concentrator cell element of claim 1 wherein the backside of the mirror element is coated with an emissive coating to provide thermal control for the mirror element and to act as a radiator fin for a solar cell means mounted thereon. 
     
     
       9. The solar concentrator cell element of claim 8 wherein said emissive coating is white paint. 
     
     
       10. The solar concentrator cell element of claim 8 wherein the organic composite material of the mirror element is infiltrated with a high thermal conductivity material. 
     
     
       11. The solar concentrator cell element of claim 10 wherein the high thermal conductivity material is silver powder. 
     
     
       12. The solar concentrator cell element of claim 8 wherein the organic composite material of the mirror element has embedded therein a metallic mesh having a high thermal conductivity. 
     
     
       13. A solar concentrator cell element array usable in outer space, which comprises: a plurality of spaced longitudinally extending mirror elements,each of which is provided with an off-axis cylindric parabolic reflective surface that is arranged to receive sunlight and to focus such sunlight in a focal line;   a solar cell means which converts received sunlight into electricity positioned on the backside of each mirror element so as to fall within the focal line of an adjacent mirror element;   a front element extending upwardly from the lower leading edge of each mirror element; and   a rear element extending downwardly from the upper trailing edge of each mirror element, the rear element of the mirror element cooperating with the front element of an adjacent mirror element to form an aperture through which the focused sunlight from a mirror is directed onto the solar cell means positioned at the focal line of the mirror element.   
     
     
       14. The solar concentrator cell element array of claim 13 which further includes side members which are secured to the ends of the spaced mirror elements. 
     
     
       15. The solar concentrator cell element array of claim 14 wherein the mirror elements, the front elements, the rear elements, and the side members comprise an organic composite material whereby the aforesaid elements are formed into a unitary integral structure. 
     
     
       16. The solar concentrator cell element array of claim 15 wherein the reflective surface of each mirror element is provided with a highly reflective metallized coating and the opposing backside of each mirror element is provide with a thermal emissive coating to enhance thermal control for the mirror element and to act as a radiator fin for a solar cell means mounted thereon.